ozone: Implement zero/one-copy texture for Ozone GBM.

ui/ozone/platform/drm/gpu/gbm_surface_factory.cc

Index: ui/ozone/platform/drm/gpu/gbm_surface_factory.cc
diff --git a/ui/ozone/platform/drm/gpu/gbm_surface_factory.cc b/ui/ozone/platform/drm/gpu/gbm_surface_factory.cc
index bb3aff7bba610640781eb940a507a1aac75a5f37..0249d26ce12d0448848f51982a265bdee1992119 100644
--- a/ui/ozone/platform/drm/gpu/gbm_surface_factory.cc
+++ b/ui/ozone/platform/drm/gpu/gbm_surface_factory.cc
@@ -7,6 +7,7 @@
 #include <gbm.h>
 
 #include "base/files/file_path.h"
+#include "base/posix/eintr_wrapper.h"
 #include "third_party/khronos/EGL/egl.h"
 #include "ui/ozone/common/egl_util.h"
 #include "ui/ozone/platform/drm/gpu/drm_device_manager.h"
@@ -23,8 +24,26 @@
 
 namespace ui {
 
+namespace {
+
+bool ShareToRenderProcess(int fd, base::FileDescriptor* new_handle) {
+  int duped_handle = HANDLE_EINTR(dup(fd));
+  if (duped_handle < 0) {
+    DPLOG(ERROR) << "dup() failed.";
+    *new_handle = base::FileDescriptor();
+    return false;
+  }
+
+  *new_handle = base::FileDescriptor(duped_handle, true);
+  return true;
+}
+
+}  // namespace
+
 GbmSurfaceFactory::GbmSurfaceFactory(bool allow_surfaceless)
-    : DrmSurfaceFactory(NULL), allow_surfaceless_(allow_surfaceless) {
+    : DrmSurfaceFactory(NULL),
+      allow_surfaceless_(allow_surfaceless),
+      drm_device_manager_(nullptr) {
 }
 
 GbmSurfaceFactory::~GbmSurfaceFactory() {
@@ -108,14 +127,11 @@ scoped_refptr<ui::NativePixmap> GbmSurfaceFactory::CreateNativePixmap(
     gfx::Size size,
     BufferFormat format,
     BufferUsage usage) {
-  if (usage == MAP)
-    return nullptr;
-
   scoped_refptr<GbmDevice> gbm = GetGbmDevice(widget);
   DCHECK(gbm);
 
   scoped_refptr<GbmBuffer> buffer =
-      GbmBuffer::CreateBuffer(gbm, format, size, true);
+      GbmBuffer::CreateBuffer(gbm, format, size, usage == SCANOUT);
   if (!buffer.get())
     return nullptr;
 
@@ -126,6 +142,22 @@ scoped_refptr<ui::NativePixmap> GbmSurfaceFactory::CreateNativePixmap(
   return pixmap;
 }
 
+base::FileDescriptor GbmSurfaceFactory::ExportDmaBuf(
+    gfx::AcceleratedWidget widget,
+    scoped_refptr<NativePixmap> pixmap) {
+  scoped_refptr<GbmDevice> gbm = GetGbmDevice(widget);
+  DCHECK(gbm);
+  DCHECK(pixmap->GetBufferUsage() == NativePixmap::MAP);
+
+  base::FileDescriptor dma_buf;
+  if (!ShareToRenderProcess(pixmap->GetDmaBufFd(), &dma_buf)) {
+    DLOG(ERROR) << "Fail to duplicate a DMA-BUF file descriptor";
+    return base::FileDescriptor();
+  }
+
+  return dma_buf;
+}
+
 bool GbmSurfaceFactory::ScheduleOverlayPlane(
     gfx::AcceleratedWidget widget,
     int plane_z_order,